Natural oils provide chemical species that differ in structure from those generally obtained from traditional petroleum refining processes. In many instances, natural oils contain multifunctional moieties that contain, among other features, an ester or acid group and an olefinic group. When natural oils are refined, the products obtained from the refining process can yield unique compounds that can serve as useful building blocks for various chemical species.
Polyurethanes are a class of polymers having chains of organic units joined by carbamate linkages, but which can include other linkages as well. In many instances, polyurethanes exist as block copolymers, where one block is formed from a prepolymer that contains carbamate linkages (e.g., a polycarbamate prepolymer) and another block is formed from another polymer, such as a polyester. Polyurethanes can have a wide variety of physical properties, which depend, among other factors, on the combination and arrangement of monomers and blocks used to make the polyurethane. In some instances, certain blocks are hard or rigid (e.g., the polycarbamate portion) while others are soft and flexible (e.g., the polyester portion). Alteration of the chemical structure, size and/or frequency of these blocks in a polyurethane can allow for modification of the properties of the resin. These options can lead to resins having a wide array of different properties. Some of these resins can be thermosetting, while others can be thermoplastic. Because such resins contain multiple blocks having different chemical features, they can also be useful as compatibilizers, e.g., in a blend.
Polyurethane foams can be used for a number of different applications. Polyurethane foams may be flexible or rigid, and can be used in a variety of different applications, including, but not limited to, use for foam insulation, use in packaging materials, and use in cushioning. Polyurethanes can also be used as elastomers. Polyurethane elastomers can be solid or porous, with representative applications including, but not limited to, textile fibers, coatings, sealants, adhesives, and resilient pads. Polyurethanes can also be used as thermosetting polymers. Representative applications of polyurethane thermosets include, but are not limited to, abrasion resistant wheels, mechanical parts, and structural materials.
It is desirable to expand the chemical structures present in polyurethanes, so as to expand the useful properties that can be provided by the polymers. For example, properties such as flexibility, toughness, etc. can be improved by incorporating chemical groups that lower the modulus or that can absorb energy, respectively. One may also be able to improve the effectiveness of the polyurethane as a compatibilizer by incorporating new chemical groups into one or more of the blocks. This expansion of chemical structures may be accomplished through post-polymerization processing, such as reaction with other reagents or blending with other polymers. It may be desirable, however, to expand the chemical structures by introducing new chemical structures in the monomeric building blocks from which the polyurethane resin is formed.
Thus, there is a continuing need to develop new materials that can be incorporated into polymeric materials, such as polyurethanes, so as to develop resins having new and useful properties. Consistent with that, there is a continuing need to expand the range of available polyester polyols that, among other available uses, can be incorporated into polyurethanes and thereby obtain resins having properties, such as compatibilizing properties, that would not otherwise be possible.